6L80 shift timing adjustments

[Estep40511]

How can I adjust the speed of the shifts under light throttle or torque, but keep the tire chirping shifts during heavy loads? It almost feels like a flare when it shifts from 2-3 or sometimes on the 5-6 shift, but only under light load conditions. Not noticing any slip, and gear ratios look spot on, etc. Is this on the transmission tune, or adjust DD?? Just curious. I dont want to lose the firm shifts under a heavy pedal, but Im afraid Im going to cause damage if this continues. I checked fluid level/condition. both excellent. just worries me. Thanks in advance!!!

[GHuggins]

This one gets into the shift times - one of cringer's vids - https://www.youtube.com/watch?v=xHIfopUUl1Q&t=1492s

BUT in actuality since it sounds like you're talking about a 5th gen, DD will change shifting and should be dialed in first if you haven't already. Before the nay sayers come in, anything torque related and not just the torque model will change the WHOLE DD table which is why it's important to dial the whole thing in. Especially if you change any of the pedal or throttle settings, but those are in the background. Just other tables I dial in when I'm doing one. Basically if you change anything influencing torque or throttle and just to name a few - torque models, MAF, VVE, pedal progression, throttle rate, speed accelerometer settings, traction control switch settings to utilize the accelerometer settings, SOI, regular rate limits and so on then it will require dialing the DD back in. For example if you do things right and dial the VVE in then that'll actually throw the torque model out worse. If you dial all of this in (torque models, DD, fuel models and so on) then it will make for a REALLY nice driving and operating vehicle. It just takes a little while dialing everything in.

This is the math formula for dialing in the DD - 100 * ([2114.156] - [2111.156]) / [2111.156] - you have to make sure you're logging those channels.


It should show a "fuel trim" value for dialing the table in. Do paste halves. If you have cam surging for example, just doing this will fix 99% of that on a fifth gen. Going back to the transmission aspect - shift lunges can pretty much be taken care of in the DD.

[yellz06]

The shift lunges will not truly be solved by the DD table. Just bandaided, specially on PD blowers. This is just how the airflow model works in the NA cals.

[GHuggins]

If you're talking about a PD blower conversion then that requires a whole lot of tables to be adjusted including background tables for the throttle to do what it's supposed to do otherwise I can't say that I've had this issue with a factory PD blower car as long as the torque models and everything were dialed in, so can't comment there.

[Estep40511]

Heres a small log of what it does when making the 5-6 shift. Doesnt do it all the time. and it does not matter is trans is cold or hot, same goes for engine. its very weird. 23-09-29 12-50-58.hpl

[Estep40511]

I posted a log of it doing it on here just now. Its weird it doesnt do it all the time. Im almost starting to wonder if I have a checkball starting to go bad in the valve body

[TransGo Robert]

I posted a log of it doing it on here just now. Its weird it doesnt do it all the time. Im almost starting to wonder if I have a checkball starting to go bad in the valve body

You are not recording enough transmission related PIDs to help much of anything in your log. You need to log ISS, OSS, TCC solenoid command and TCC slip as well as line pressure solenoid command.

[hjtrbo]

Post a tune up mate, and do what Rob said.
Screenshot 2023-10-02 101306.pngScreenshot 2023-10-02 101549.png

[Estep40511]

Post a tune up mate, and do what Rob said.
Screenshot 2023-10-02 101306.pngScreenshot 2023-10-02 101549.png

I will do that today. And get those other PIDS in the log

[Estep40511]

You are not recording enough transmission related PIDs to help much of anything in your log. You need to log ISS, OSS, TCC solenoid command and TCC slip as well as line pressure solenoid command.

Heres a log of my drive back to work after lunch. Only got it to mess up going into 6th once. and will post tune as well

23-10-02 12-57-19.hpl

1022023.hpt

[TransGo Robert]

Heres a log of my drive back to work after lunch. Only got it to mess up going into 6th once. and will post tune as well

Hopefully guys on here that know more about tuning then me can point out what is not setup right in the tune to cause this, but man that is a God awful command for the 2-6 clutch during both the 1-2 and the 5-6 shift. You just can't feel it on the 1-2 because nothing releases but if you keep driving it like that it will fry the 2-6 for sure.

[Estep40511]

[QUOTE=TransGo Robert;750366]

Heres a log of my drive back to work after lunch. Only got it to mess up going into 6th once. and will post tune as well

Hopefully guys on here that know more about tuning then me can point out what is not setup right in the tune to cause this, but man that is a God awful command for hte 2-6 clutch during both the 1-2 and the 5-6. You just can't feel it on the 1-2 because nothing releases but if you keep driving it like that it will fry the 2-6 for sure.

I lowered pressures some and played around with the shift timing and inertia factors. Seems to have helped it a bunch.

[Estep40511]

UPDATE: took valve body apart, #6 check ball was gone and 2-6 valve had a groove in it where it moves in valve body. Replaced valve body and filter.....good as new! crazy it shifted at all with the check ball gone. Usually on the stock ones here at work youd get a harsh shift or no Drive at all.

[TransGo Robert]

UPDATE: took valve body apart, #6 check ball was gone and 2-6 valve had a groove in it where it moves in valve body. Replaced valve body and filter.....good as new! crazy it shifted at all with the check ball gone. Usually on the stock ones here at work youd get a harsh shift or no Drive at all.

Glad you found the problem, hopefully the 2-6 did not get hurt too bad in there and still have plenty of life left. Checkball # 6 missing does not cause much and it is almost impossible to feel it by the seat of the pants. It does nothing at all in 1-2-3-4-5-6 as it is pushed out of the way by the fluid, it only comes into action when you go to P/R/N from the drive position. It force the 1-2-3-4 clutch fluid through an orifice to smooth out the release to help avoid driveline clunks. The one that cause no movement when it shrink that we see all the time is checkball # 1, that one is different because it is in a bath tubs. The ones that cause harsh shifts are the one that force fluid through an orifice during the apply of a clutch like checkaball # 7 for the 3-5-R.

[Estep40511]

Glad you found the problem, hopefully the 2-6 did not get hurt too bad in there and still have plenty of life left. Checkball # 6 missing does not cause much and it is almost impossible to feel it by the seat of the pants. It does nothing at all in 1-2-3-4-5-6 as it is pushed out of the way by the fluid, it only comes into action when you go to P/R/N from the drive position. It force the 1-2-3-4 clutch fluid through an orifice to smooth out the release to help avoid driveline clunks. The one that cause no movement when it shrink that we see all the time is checkball # 1, that one is different because it is in a bath tubs. The ones that cause harsh shifts are the one that force fluid through an orifice during the apply of a clutch like checkaball # 7 for the 3-5-R.

I lowered my pressures some. Going to play around with the shift timing a little and inertia factors. I want it to shift like a Corvette 6L80 does.

[TransGo Robert]

I lowered my pressures some. Going to play around with the shift timing a little and inertia factors. I want it to shift like a Corvette 6L80 does.

If you ever have to take the transmsision out down the road, put our TOW&PRO https://transgo.com/product-details/6l80towpro/ kit in it, you will love the way it shifts.

[Estep40511]

If you ever have to take the transmsision out down the road, put our TOW&PRO https://transgo.com/product-details/6l80towpro/ kit in it, you will love the way it shifts.

nice Ill definitely try that out. My trans is coming back out this winter to upgrade the converter. Do you guys sell clutch kits too?

[TransGo Robert]

nice Ill definitely try that out. My trans is coming back out this winter to upgrade the converter. Do you guys sell clutch kits too?

No we do not sell any of the regular stuff needed to rebuild transmissions. We specialize in kit to either correct know OE issues and/or modify them so that the friction elements can hold more torque and get a better shift feel.

[Estep40511]

Seems fine now. Just wish I could quicken up the shifts and keep the firm shift under harder throttle. Ill mess with the torque adder tables some. is there a limit you can go on those tables, as in whats considered too high of a setting ? thanks in advance.

[hjtrbo]

Everyone's got there own take. These are some basic shift suggestions.
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